public enum Day { 
    SUNDAY, 
    MONDAY, 
    TUESDAY, 
    WEDNESDAY, 
    THURSDAY, 
    FRIDAY, 
    SATURDAY
}
    //使用案例
class EnumExample {  
        public static void main(String[] args) {  
            Day day = Day.MONDAY;  
            switch (day) {  
                case MONDAY:  
                    System.out.println("It's Monday!");  
                    break;  
                case TUESDAY:  
                    System.out.println("It's Tuesday!");  
                    break;  
                // 其他天数的情况...  
                default:  
                    System.out.println("It's some other day.");  
            }  
        }   
    }